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Updated: Dec 5, 2025
Author Spotlight: An Automated Method for Assessing Visual Acuity in Infants and Toddlers Using an Eye-Tracking System
Published on: March 17, 2023
Automated Visual Acuity Evaluation Based on Preferential Looking Technique and Controlled with Remote Eye Tracking
Nika Vrabič1, Bor Juroš2, Manca Tekavčič Pompe3,4
1Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
Insights
An automated visual acuity test (AVAT) using preferential looking and eye tracking was validated in healthy children. AVAT results showed good agreement with standard tests, offering a comparable method for assessing visual acuity.
Area of Science:
- Ophthalmology
- Pediatric Medicine
- Biomedical Engineering
Background:
- Assessing visual acuity (VA) in infants and young children presents significant challenges.
- Standard tests (ST) for pediatric VA often require specialized training and can be time-consuming.
- Developing objective and automated methods for VA assessment is crucial for early detection of visual impairments.
Purpose of the Study:
- To develop and validate an Automated Visual Acuity Test (AVAT) for infants using preferential looking and remote eye tracking.
- To compare the VA measurements obtained from AVAT with those from traditional standard tests (ST) in healthy children.
- To assess the feasibility and reliability of AVAT in a pediatric population.
Main Methods:
- A group of 36 healthy children underwent both standard visual acuity testing (Keeler Acuity Cards or LEA symbols) and the novel AVAT.
- AVAT presented stimuli with varying spatial frequencies, and a remote eye tracker monitored children's visual attention to target stimuli.
- Binocular VA was calculated based on the proportion of time spent looking at the target stimuli compared to a control background.
Main Results:
- The AVAT successfully completed by 97% (35/36) of the children, demonstrating high feasibility.
- A moderate agreement (Lin's concordance coefficient = 0.53) was found between AVAT and standard test VA values.
- A slight tendency for AVAT to overestimate VA in children with better vision and underestimate in those with poorer vision was noted.
Conclusions:
- The Automated Visual Acuity Test (AVAT) is a viable and comparable alternative to standard tests for assessing visual acuity in healthy children.
- AVAT requires minimal investigator skill, making it potentially more accessible for routine pediatric eye examinations.
- Further research may refine AVAT for improved accuracy across the full spectrum of visual acuity.
Objective:
To establish an automated visual acuity test (AVAT) for infants, based on preferential looking technique and controlled with remote eye tracking. To validate the AVAT in a group of healthy children. To compare AVAT visual acuity (VA) values with corresponding VA values acquired with standard tests (ST).
Methods:
ST, adapted for age (Keeler Acuity Cards in preverbal children and LEA symbols in verbal children), was performed to obtain monocular VA in a group of 36 healthy children. During AVAT, 9 different stimuli with grating circles that matched spatial frequencies of 9 Keeler Acuity Cards (ranging between 0.29 and 14.5 cycles per degree) were projected on a screen. Three repetitions of each stimulus were shown during 9-s intervals, interchanging with an attention grabber. The remote eye tracker was used to evaluate the proportion of time a child spent looking at each grating circle compared to a homogeneous gray background that matched the grating stimuli in average luminance. From this proportion of time, child's binocular VA was evaluated.
Results:
Ninety-seven percent (35/36) of healthy children successfully completed ST and AVAT. There was an agreement between the results of an ST and AVAT, with Lin's concordance coefficient being 0.53 (95% CI = 0.31-0.72). A tendency was observed toward VA overestimation on AVAT for children with VA >0.4 logMAR on ST and toward VA underestimation on AVAT for children with VA ≤0.4 logMAR on ST.
Conclusions:
AVAT requires a minimally skilled investigator. The evaluation of better eye monocular VA on ST and binocular VA on AVAT was comparable for healthy children.
